Effects of temperature on the physiological performance of two non-native C4 species
(2024) BION02 20232Degree Projects in Biology
- Abstract
- This experiment studied the performance of two closely related C4 grass species, Eragrostis minor and E. multicaulis. Both species are non-native to Sweden but have colonised the city of Malmö at different times over the last century. Multiple vegetative and reproductive performance traits were compared across four temperature regimes ranging from 19 to 40°C. The two species were found to have significantly different response curves to increasing temperature despite their close genetic relatedness, possibly explaining their different colonisation histories in the study area. No strong evidence of local adaptation was found when comparing populations from the introduction site with ones established further inland. Growing each species in... (More)
- This experiment studied the performance of two closely related C4 grass species, Eragrostis minor and E. multicaulis. Both species are non-native to Sweden but have colonised the city of Malmö at different times over the last century. Multiple vegetative and reproductive performance traits were compared across four temperature regimes ranging from 19 to 40°C. The two species were found to have significantly different response curves to increasing temperature despite their close genetic relatedness, possibly explaining their different colonisation histories in the study area. No strong evidence of local adaptation was found when comparing populations from the introduction site with ones established further inland. Growing each species in competition with the other seemed to enhance existing species differences. (Less)
- Popular Abstract
- Watching grass grow (at different temperatures)
As the Earth’s climate changes and temperatures rise, many plant species will likely expand their range towards areas that were previously too cold for them to grow in. In recent decades, many species characteristic to warmer regions have begun spreading throughout northern areas, in some cases even becoming invasive and threatening local flora. Here, I focus on two plants that have recently made their way north, Eragrostis minor and Eragrostis multicaulis, also known as lovegrasses. These grasses have spread throughout Europe over the last century and have even been found in southern Swedish cities such as Malmö.
E. minor and E. multicaulis are both C4 plants – a term referring to... (More) - Watching grass grow (at different temperatures)
As the Earth’s climate changes and temperatures rise, many plant species will likely expand their range towards areas that were previously too cold for them to grow in. In recent decades, many species characteristic to warmer regions have begun spreading throughout northern areas, in some cases even becoming invasive and threatening local flora. Here, I focus on two plants that have recently made their way north, Eragrostis minor and Eragrostis multicaulis, also known as lovegrasses. These grasses have spread throughout Europe over the last century and have even been found in southern Swedish cities such as Malmö.
E. minor and E. multicaulis are both C4 plants – a term referring to plants that have evolved a much more heat-adapted metabolism compared to many other species. Plants with this type of metabolism have historically been found mainly in warmer areas, since their optimal temperature for photosynthesis is around 40°C. The two grasses this study focused on are native to Southern Europe, Southern Asia, and parts of Africa. The older newcomer is E. minor, which was first recorded in Malmö in the 1900s but only began spreading throughout the city the 1990s. The second grass, E. multicaulis, arrived in 2017 and immediately began spreading outwards. Their seeds were likely brought over with cargo ships and accidentally deposited around Malmö harbour, but the true question is how they managed to survive in the lower Swedish temperatures.
In this study, I tested the growth of these two grass species at four different temperatures from 19 to 40°C. I also compared two different populations of each species, one taken from around the harbour and another from the opposite end of the city, to see if the plants that have managed to spread further are in some way adapted to lower temperatures. Finally, I also compared the growth of the two grasses when planted individually or in competition with the other species, to see which of the two species performs better under the stress of competition.
I found that the two grasses responded very differently to the four growth temperatures. For the most part, E. minor grew faster and produced more seeds than E. multicaulis, but its seeds had more trouble germinating at low temperatures. What was especially interesting is that neither species performed well at 19°C – while this can be expected of C4 plants, it is still surprising that they have established themselves in Sweden, where average summer temperatures are often this low. What’s more, inland populations did not seem to be any more cold adapted than those still in the harbour, and competition made the plants’ performance predictably worse. A possible explanation for how these grasses survive in Malmö is a phenomenon called UHI, or the urban heat island effect. This refers to the fact that the temperature in Northern hemisphere cities is usually several degrees warmer than that of surrounding areas, mostly because building and road materials retain heat better and for longer. Combined with the rising temperatures that have been recorded for Swedish summers since the 1990s, this effect has likely made Malmö warm enough in the summer for the two Eragrostis grasses to thrive in.
Master’s Degree project in Plant Ecology, 45 credits, 2024
Department of Biology, Lund University
Advisor: Stefan Andersson
Department of Biology (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9154703
- author
- Krasteva, Magdalena
- supervisor
- organization
- course
- BION02 20232
- year
- 2024
- type
- H2 - Master's Degree (Two Years)
- subject
- language
- English
- id
- 9154703
- date added to LUP
- 2024-05-27 15:56:07
- date last changed
- 2024-05-27 15:56:07
@misc{9154703,
abstract = {{This experiment studied the performance of two closely related C4 grass species, Eragrostis minor and E. multicaulis. Both species are non-native to Sweden but have colonised the city of Malmö at different times over the last century. Multiple vegetative and reproductive performance traits were compared across four temperature regimes ranging from 19 to 40°C. The two species were found to have significantly different response curves to increasing temperature despite their close genetic relatedness, possibly explaining their different colonisation histories in the study area. No strong evidence of local adaptation was found when comparing populations from the introduction site with ones established further inland. Growing each species in competition with the other seemed to enhance existing species differences.}},
author = {{Krasteva, Magdalena}},
language = {{eng}},
note = {{Student Paper}},
title = {{Effects of temperature on the physiological performance of two non-native C4 species}},
year = {{2024}},
}